【摘要】 目的探讨内质网应激(ERS)在大鼠缺血再灌注损伤心肌中的表达以及小剂量衣霉素(TM)预处理对缺血再灌注损伤心肌的影响。方法 SD大鼠30只随机分为三组,假手术组(Sham组)、缺血再灌注组(IR组)、衣霉素处理+IR组(TM+IR组),每组10只。Sham组单纯开胸,不结扎冠状动脉;IR组开胸,结扎前降支30 min,再灌注2 h;TM+IR组TM腹腔注射0.6 mg/kg,30 min后结扎前降支30 min,再灌注2 h。于开胸后,心肌再灌注2 h抽血,检测肌钙蛋白I(c Tn I)含量,透射电镜观察再灌注2 h心肌的超微结构,检测再灌注2 h心肌的GRP78 mRNA及蛋白表达。结果 IR组和TM+IR组在再灌注2 h时,c Tn I水平均明显上升;IR组心肌超微结构损伤最严重,TM+IR组次之。再灌注2 h后,GRP78 mRNA及蛋白,IR组及TM+IR组明显升高。结论 MIRI可诱导ERS,小剂量TM预处理可减轻MIRI。更多还原

【Abstract】 Objective To explore the expression of endoplasmic reticulum stress( ERS) in rat myocardium with ischemia-reperfusion injury and the effect of preconditioning with small-dose tunicamycin on myocardium with ischemia-reperfusion injury. Methods Thirty SD rats were randomly divided into 3 groups including sham-operation group( Sham group), ischemia-reperfusion injury group( IR group) and tunicamycin + ischemia-reperfusion injury( TM + IR group),ten rats in each group. Simple thoracotomy without coronary artery ligation was performed in the Sham group. Thoracotomy and two-hour reperfusion after30 minutes of the anterior descending coronary artery ligation were performed in the IR group. In the IR + TM group,ligation of the anterior descending coronary artery for 30 minutes was performed after 30 minutes of intraperitoneal injection with tunicamycin( 0. 6ml/kg),then two-hour reperfusion was conducted. The content of cardiac troponin I( c Tn I) was detected after thoracotomy and after 2 hours of cardiac reperfusion. The myocardial ultrastructure was observed under transmission electron microscope and the expressions of myocardial glucose regulated protein 78( GRP78) mRNA and protein were detected after 2 hours of reperfusion. Results The c Tn I levels were significantly increased in the IR group and TM + IR group at 2hours after reperfusion. The damage of myocardial ultrastructure was the most severe in the IR group,and was the second severe in the TM + IR group. GRP78 mRNA and protein expressions increased significantly in the IR group and TM + IR group at 2 hours after reperfusion. Conclusion Myocardial ischemia-reperfusion injury( MIRI) may induce ERS. And preconditioning with small-dose tunicamycin may alleviate MIRI.更多还原